As photoelectric conversion devices, there are devices including a light-absorbing layer comprised of a chalcopyrite-based group I-III-VI compound semiconductor such as CIGS. Japanese Patent Application Laid-Open No. 2000-156517 discloses an example in which a light-absorbing layer comprised of a group I-III-VI compound semiconductor is provided on a backside electrode formed on a substrate. A buffer layer comprised of ZnS, CdS, or the like and a transparent conductive film comprised of ZnO or the like are formed on the light-absorbing layer.
In those photoelectric conversion devices, the diffusion length of minority carriers (electrons) generated in the light-absorbing layer is reduced due to a large number of defects present in a light-absorbing layer. As a result, in some cases, the minority carriers disappear due to the recombination with holes before being extracted by electrodes or the like. In particular, the minority carriers generated in the light-absorbing layer on the backside electrode side have to be diffused over a long length, and thus are susceptible to the defects present in the light-absorbing layer. This may lead to a decrease in photoelectric conversion efficiency.